Tooth pulp pain is considered to be a good model for human pain studies because it simulates clinical pain. Electrical tooth pulp stimulation has been modified to permit the measurement of several pain response parameters, such as pain threshold, drug request point and pain tolerance following psychophysical methodology, utilizing both classical techniques and sensory decision theory. The applicability of this laboratory procedure for human analgesic assays will be investigated. Pain response parameters obtained with tooth pulp stimulation will be compared with those obtained from other laboratory pain-induction methods, involving electrical, mechanical and thermal stimuli. Pain response parameters from several pain-induction methods, including tooth pulp stimuaation, and personality variables obtained from standard psychological tests will be subjected to the statistical method of factor analysis to isolate specific pain factors, similar to those previously identified by Wolff (1977) and Timmenmans and Sternbach (1975). All studies will use paid, healthy adult volunteers.